package com.atguigu.springcloud.lb.impl;

import com.atguigu.springcloud.lb.ILoadBalancer;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.stereotype.Component;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

/**
 * @author : wenchao.long
 * @date : Created in 2020/12/13 17:30:32 周日
 * @description :
 */
@Component
@Slf4j
public class LoadBalancerImpl implements ILoadBalancer {

    private AtomicInteger atomicInteger;

    public LoadBalancerImpl() {
        atomicInteger = new AtomicInteger(0);
    }

    @Override
    public ServiceInstance instances(List<ServiceInstance> serviceInstances) {
        int index = getAndIncrement() % serviceInstances.size();
        return serviceInstances.get(index);
    }

    public final int getAndIncrement() {
        int current;
        int next;
        do {
            current = this.atomicInteger.get();
            next = current >= Integer.MAX_VALUE ? 0 : current + 1;
        } while (!this.atomicInteger.compareAndSet(current, next));
        log.info("第几次访问，次数-> next===========" + next);
        return next;
    }

}
